Method of making phenylglycine bodies



LEE E. H. CONE, OF SYRACUSE, NEW YORK, ASSIGN'OR TO DOW CHEMICAL COMPANY, OF MIDLAND, MICHIGAN, A CORPORATION OF MICHIGAN.

METHOD OF MAKING- PHENYLGLYCINE BODIES.

No Drawing.

T 0.aZl whom it may concern:

Be it known that I, LEE E. H. CONE, a citizen of the United. States, and a resident of Syracuse, county of Onondaga, and State of l\ew York, have invented a new and useful Improvement in Methods of Making Phenylglycine Bodies, of which the following is a specification, the principle of the 1nvention being herein explained and the best mode in which I have contemplated applying that principle, so as to distinguish it from other inventions.

As is well known, Heumann, in his original process for making synthetic indigo, or rather the indoxyl from which indigo is readily derived, used phenyl glycine or phenyl glycocol. Such phenyl glycine, which can also be regarded as phenylamidoacetic acid, was obtained by the action of chlor-acetic acid on aniline. Considerable difiiculty, however, seems to have been experienced in preparing indigo thus from aniline, whether using the Heumann process proper of the various improvements which from time to time have been made therein, partly because of the poor yield from the fused phenyl glycine, and partly on account of the considerable difliculties presented in practice by the apparently simple conversion of aniline and chlor-acetic acid into phenyl-amidoacetic acid (see Bliichers Modem Industrial Chemistry, p. 345.)

In my Patent Reissue No. 14,364, dated September 25, 1917. I describe an improved method of fusing the phenyl glycine and subsequently treating the same, whereby I have been able to overcome the difliculties heretofore encountered inthis stage of the Heumann process. By the improvements now to be described, I have found it possible to correspondingly overcome the difiiculties 'ust referred to above as being encountered in making such phenyl glycine. The present improvements, in other words, have as their object the control of the reaction between chloracetic acid and aniline in such manner as to prevent the formation of undesirable by-products. Further objects are to economize in the use of the reagents employed in the reaction, and facilitate the operation by a proper sequence of steps.

To the accomplishment of the foregolng and related ends, the invention, then, con- Specification of Letters Patent.

Application filed March 22, 1918.

Patented June 13, 1922.

Serial No. 224,062.

sists of the steps hereinafter fully described and particularly pointed out in the claims, the following description settlng forth only one method of carrying out my improved process, and it being understood that various changes may be made therein, all within the scope of the invention.

In carrying out my improved method or process, I first make a dilute solution of a suitable chlor-acetic compound, preferably the sodium salt of the acid, by dissolving approximately 116.5 parts thereof by weight in 500 parts of water. Water containing aniline in solution approximately to the point of saturation, derived from a subsequent stage in the process, is used forthus dissolving the sodium chlor-acetate, since I have found that where the solution is fairly cold initially and the salt is added quickly, no appreciable reaction will occur between the salt and the aniline.

Equally satisfactory results follow where, instead of thus dissolving the salt in the aniline solution, the proper amount of soda ash is thus dissolved, and an equivalent quantity of chlor-acetic acid thereupon added. vantage that it avoids the necessity of preparing sodium chlor-acetate in a solid state.

The solution of sodium chlor-acetate thusprepared is then fed gradually into a relatively large body of aniline solution with undissolved aniline present in proper amount for the reaction. In other words, there is sufficient aniline present to complete the reaction and yet maintain the solution at all times in fully saturated state as regards such aniline. In the above specific example about two thousand parts of water, or

mother liquid derived from a subsequent.

stage of the process saturated with aniline at the boiling point, and 186 parts of aniline are used. Preferably this body of aniline solution with free aniline present is main tained at approximately boiling temperature, since a larger percentage of aniline will then dissolve. The excess aniline is to be kept well mixed with the solution by suitable stirring or rapid boiling. The solution is thus stirred or agitated, as Well as kept at the boiling point all the while the previously described solution of sodium chlor-aceta-te is fed therein.

' may remain over,

The reaction that occurs between aniline and chlor-acetic acid may be represented by the following formula-:-

After the reaction is complete, enough of the resulting solution is distilled off to drive out any excess of undissolved aniline that h but this operation is stopped 1 short of driving out the aniline which will remain dissolved in the water at the temperature to which the solution is subsequently cooled.

The aniline salt of phenyl glycine is now caused to crystallize and precipitate out of this solution by cooling the mixture being at the same time agitated so as to prevent the caking of the salt. The salt will crystallize out the more completely because the water is saturated. with aniline, and the small amount that may be left in solution is not lost, since the residual solution from this step, after the addition of the proper amount of aniline and bringing back to the original volume, may be utilized in the first step,'viz., may be treated with a fresh-batch of sodium chlor-acetate solution as has already been described.

This second batch is carried through the process in the same manner as before, repeating the subsequent steps and leaving a final solution of aniline with a small amount of phenyl glycine just as before. There will, however, be a larger amount of sodium chloride present in such solution, and the accumulation of this salt will, after three or more repetitions of the cycle, be so large as to make it undesirable to use the solution over again. When this stage is reached all the aniline in the solution is distilled off, and if desired the small content of phenyl glycine in such final mother liquor may be likewise recovered.

It will be understood that the aniline salt of phenyl glycine which results from the foregoing reaction is readilyconverted into an alkali salt, i. e., either potassium or sodium phenyl glycine, suitable for use in the fusion process where idoxyl proper is made. This conversion, however, is not a matter of interest in the present connection, forming no part of the'invention in hand. Before such conversion or other treatment, such salt is desirably washed with a cold watery saturated aniline solution, in order to remove any traces of sodium choride that mi ht otherwise adhere.

6ther modes of applying. the principle of the following claims or the equivalent of. such stated step or steps be employed.

I therefore particularly point out and distinctly claim as my invention 1. In a method of making phenyl-glycine bodies, the steps which consist in dissolving a salt of chlor-acetic acid in a cold watery solution of aniline; and then adding the solution thus formed to a hot watery solution of aniline, whereby the aniline salt of phenyl-glycine is formed.

2. In a method of making phenyl-glycine bodies, the steps which consist in dissolving a salt of chlor-acetic acid in a cold watery solution of aniline; and then adding the solution thus formed to a watery solution of aniline kept at approximately the boiling point, whereby the aniline salt of phenyl-glycine is formed.

3. In a method of making phenyl-glycine bodies, the steps which consist in dissolving a salt of chlor-acetic acid in a cold solution of aniline; gradually adding the solution thus formed to a hot watery solution of aniline; and maintainin the latter in approximately saturated con( ition in respect to aniline during the reaction, whereby the aniline salt of phenyl-glycine is formed.

4. In a method of making phenyl-glycine bodies, the steps which consist in dissolving a salt of chlor-acetic acid in a cold watery solution of aniline; gradually adding the solution thus formed to a hot watery solution of aniline with undissolved aniline present in proper amount for the reaction; and stirring the mixture so as to maintain such aniline solution in approximately saturated condition during the reaction, whereby the aniline salt of phenyl-glycine is formed.

5. In a method of making phenyl-glycine bodies, the steps which consist in gradually adding a dilute solution of a suitable salt of chlor-acetic acid to a relatively large body of watery aniline solution with undissolved aniline present in amount sufficient for the reaction; and stirring the mixture so as to maintain such aniline solution in approximately saturated condition during the reaction, whereby the aniline salt of phenylglycine is formed.

6. In a method of making phenyl-glycine bodies, the steps which consist in gradually adding a dilute solution of an alkali metal salt of chlor-acetic acid to a relatively large body of watery aniline solution with undissolved aniline present in amount suiiicient vided. the step or steps stated by any one Miarao for the reaction; heating the mixture, and

stirringthe same so as to maintain such aniline solution in approximately saturated condition during the reaction, whereby the aniline salt of phenyl-glycine is formed.

7. In a method of making phenyl-glycine bodies,the steps Which consist in gradually adding a dilute solution of sodium chloracetate in cold Water saturated with aniline to a relatively large body of hot watery aniline solution with undissolvedaniline present in amount suiiicient for theireaction; and heating and stirring the mixture so as to maintain such aniline solution in approxi-' mately saturated condition during the reaction, whereby the aniline salt of phenylglycine is formed.

8. In a method of making phenyl-glycine bodies, the steps which consist in dissolving a salt of chlor-acetic acid in a cold watery solution of aniline; adding the solution thus formed to a hot watery solution of aniline; maintaining the latter in approximately saturated condition during the reaction, whereby the aniline salt of phenyl-glycine is formed; distilling ofi' any excess of undissolved aniline after the reaction is complete; and then cooling the residual solution so as to crystallize out such phenyl-glycine salt.

9. In a method of making phenyl-glycine bodies, the steps which consistin dissolving a salt of chlor-acetic acid in a cold watery solution of aniline; adding the solution thus formed to a hot watery solution of aniline; maintaining the latter in approximately saturated condition during the reaction, whereby the aniline salt of phenyl-glycine is formed; cooling the residual solution so as to crystallize out such phenyl-glycine salt; filtering out such phenyl-glycine salt; and then adding aniline to the mother liquor, diluting same approximately to the volume of aniline solution used in the first step, treating with chlor acetic compound and repeating the succeeding steps as before.

10. In a method of making phenyl-glycine bodies, the steps which consist in adding a solution of a salt of chlor-acetic acid to a watery solution of aniline; maintaining the latter in approximately saturated condition during the reaction, whereby the aniline salt of phenyl-glycine salt is formed; distilling off any excess of undissolved aniline, after the reaction is'complete; cooling the residual solution so as to crystallize out such phenylglycine salt; and then separating such salt and Washing the sam with cold saturated watery aniline solution to remove the sodium chloride.

l1. In a process of making phenyl-glycine bodies, the step which consists in washing the freshly precipitated phenyl-glycine salt with a cold Watery aniline solution.

12. In a process of making phenyI-glycine bodies, the step which consists in washing the freshly precipitated phenyl-glycine salt with a cold watery saturated aniline solut1on.

Signed by me, this 18th day of March, 1918. I

LEE E. H, CONE. 

